1. Field of the Invention
This invention relates generally to digital communication systems and methods, and more particularly to a method of implementing a Viterbi algorithm (VA) for trellis coded modulation (TCM) decoding, optionally in association with a digital signal processor (DSP) or other data processor.
2. Description of the Prior Art
The upstream physical layer of the new DOCSIS 2.0 specification uses advanced time-division multiple access (A-TDMA) or synchronous code-division multiple access (SCDMA) burst type formats. For SCDMA, the signal processing sequence for the transmitter 10 is illustrated in FIG. 1. The modulation scheme includes Reed-Solomon (RS) encoding 12, optional trellis coded modulation (TCM) coding 14, a unique SCDMA framing scheme 16, and symbol mapping 18 into various constellations depending on the TCM mode used. Furthermore, in TCM mode, a special RS-bytes to TCM-input-bits mapping is used at the TCM encoder input.
In view of the foregoing, it would be both desirable and advantageous in receiver applications, for example burst receiver such as the SCDMA burst receiver implemented, for example, in DOCSIS2.0 standard, to provide a method of implementing a Viterbi algorithm (VA) for trellis coded modulation (TCM) decoding, optionally in association with a digital signal processor (DSP) or other data processor.